FIELD OF THE INVENTION
The present invention relates generally to an information processing system including a console. More specifically, the invention relates to an apparatus and method for providing highly reliable connection of an operator console.
In the conventional console connection method, a main console and an auxiliary console are connected to a central processing unit (CPU) simultaneously to provide for increased reliability. In this case, the main console and the auxiliary console are each connected to the CPU through respectively corresponding interfaces.
However, in such a conventional method, since the main console and the auxiliary console are simultaneously connected to the CPU via two interfaces, an extra interface which could otherwise be used for another purpose is occupied. Also, since the main console and the auxiliary console have to be controlled simultaneously, the load on the controlling software is increased.
Therefore, one can consider a method to commonly use a single interface for the main and auxiliary consoles so that connection with the CPU is changed over from one console to the other when failure is caused in one console.
However, the foregoing method is not always effective since if a critical failure is caused in the console, the faulty console may not generate a connection demand to the CPU. In such a case, the CPU cannot be controlled, possibly causing shutdown of the overall system.